Method and apparatus for manufacturing pressurized packaging body

ABSTRACT

A method and apparatus for manufacturing pressurized packages capable of obtaining gas displacement pressurized canned goods with high accuracy of internal pressure by atomizing liquid nitrogen, and supplying it together with low temperature vaporized gases to a head space of a can. A spray device assembly ( 10 ) for atomizing and spraying the liquid nitrogen is provided in an opening of the bottom of a liquefied gas storage tank ( 1 ) formed as a vacuum heat insulating structure. The spray device assembly ( 10 ) is constituted such that a valve ( 2 ) for controlling the flow rate of liquid nitrogen, a spray nozzle ( 3 ), a liquid nitrogen flowpassage ( 4 ) extending from the valve ( 2 ) to the spray nozzle ( 3 ), a nozzle cooling tank ( 5 ) for cooling the flowpassage, and a purge device for cutting an outer peripheral portion of a nozzle and an outlet portion off from the air, so as to prevent them from being frosted, are integrally mounted on a spray body  6.  The nozzle cooling tank ( 5 ) always cools the pipe  13  and the nozzle  3  by liquid nitrogen, and enables supplying of the liquid nitrogen to the nozzle having a temperature gradient to the neighborhood of a boiling point, without boiling and vaporizing it from the tank to the nozzle. The liquid nitrogen supplied while preventing of being vaporized to an orifice inlet of the spray nozzle allows to pass through a nozzle orifice in the liquid state to release into the atmosphere, thereby giving rise to a rapid vaporizing expansion immediately after moving out of the nozzle orifice, so that other liquid nitrogen still in the liquid phase state is atomized.

TECHNICAL FIELD

This invention relates to a method and apparatus for manufacturing a gasdisplacement pressurized packaging body in containers such as cans forcanned goods, molded containers, plastic bottles, and glass bottles,etc., and more particularly to a method and apparatus for manufacturinga pressurized packaging body wherewith the inert gas displacement ratiocan be increased, container internal pressures can be stably obtainedthat are suitable positive pressures, small volume injecting of a liquidinert gas can be done with high precision, and low pressurized packagingbodies can be obtained which exhibit outstanding guaranteed quality.

BACKGROUND ART

Conventionally, in manufacturing canned goods, a pressurized cannedgoods manufacturing method is commonly employed wherein the head spaceof the can is injected with an inert gas (which is ordinarily liquidnitrogen and therefore hereinafter represented by liquid nitrogen) thatis made to flow down while the can is being conveyed from the filler tothe seamer, and the can is seamed and sealed while the vaporizingexpansion of the liquid nitrogen is continuing, whereby an internalpressure is produced by the vaporizing expansion of remaining liquidnitrogen after sealing. The main objective in injecting the liquidnitrogen and causing a positive pressure to be generated in the can isto give rigidity to the can by the positive pressure, thus making itpossible to use thinner walled materials for the can and to reduce theamount of material used. Moreover, by displacing the gas (air) insidethe can with nitrogen (inert gas) and removing the oxygen, the benefitof preventing flavor deterioration due to oxidation of the contents isalso gained. Another objective is to aggressively make the pressureinside the can either positive or negative, and then perform aninspection to determine whether the pressure inside the can is beingheld at a prescribed pressure or not, thereby making it possible todetect leakage of the canned goods and spoilage in the contents due tobacterial incursion, and hence to guarantee that the contents are safe.

However, with the conventional method wherein liquid nitrogen is sealedin and an internal pressure is produced, there is a drawback thatfluctuation of the injected liquid nitrogen volume is significant andthe prescribed internal pressure can not be stably obtained,particularly because the liquid nitrogen splashes out to the outside ofthe can during liquid nitrogen injection and during lid seaming. Forthat reason, there is a problem that the material used for the cancannot be made thin to the limit of what can withstand the prescribedinternal pressure, and the quantity of material used cannot be reducedeffectively. When a small volume of liquid nitrogen is injected, inorder to obtain low internal pressure cans, the fluctuation relative tothe target injecting volume becomes significantly larger, wherefore ithas not been possible to stably obtain low pressurized cans by injectingsmall volumes of liquid nitrogen with the conventional liquid nitrogeninjection method. In the case of easily spoilable liquid content such asbeverages containing milk, vacuum cans or low pressurized cans aredemanded wherewith it is easy to detect swelling caused bymicroorganisms. However, when the internal pressure fluctuation issignificant as described above, it can no longer be determined whetherswelling is caused by microorganisms or by fluctuation in internalpressure resulting from liquid nitrogen injection. For that reason,until now, the easily spoilable liquid content have had to fill withthick walled cans because means for enhancing can strength by producinga pressure inside the cans by injecting liquid nitrogen could not beemployed.

Furthermore, with the conventional liquid nitrogen injection method,internal pressure fluctuation in pressurized cans also happens as aresult of the fluctuation in the amount of filling contents. That is,even supposing that the definite volume of liquid nitrogen remains, whenthe volume of filling contents increases (that is, the head spacedecreases), the internal pressure increases due to vaporizing expansionof the liquid nitrogen. Therefore, in order to obtain accurate internalpressure, the liquid nitrogen injection volume must be controlledaccording to the fluctuation of the filling content volume. It has beenimpossible to achieve this with the conventional method.

It has also been proposed that the liquid nitrogen be atomized and theninjected (Japanese Patent Publication No. S59-9409/1984). However,unlike with ordinary liquids having a high boiling point, liquidnitrogen that have a boiling point of −196° C. at atmospheric pressureand vaporizes very easily, atomization cannot be done stably even whenit is sprayed under pressure, wherefore this method has not yet beenmade practical. The cause for this is that, when liquid nitrogen issprayed to the atmosphere, the liquid nitrogen is heated and vaporizedby the atmosphere at room temperature, whereupon vaporization occurs inthe spray nozzle prior to atomization, causing pressure fluctuations andfoam gripping at the spray orifice, which causes pulsation. Inparticular, when spraying is done under high pressure, the boiling pointdecreasing when the liquid nitrogen is passing through the spray nozzlebecomes large, the liquid nitrogen boils inside the nozzle, pulsationoccurring, whereupon fine particles cannot be stably obtained. Anothercause is that the moisture contained in the atmosphere freezes at thenozzle tip, blocking the spray orifice and resulting in unstable sprayvolume. Even assuming that stable atomization can be effected, thefilling accuracy of the fine particles of liquid nitrogen injected inthe container will be poor unless the injected liquid nitrogen spraypattern is consistent with the direction of conveyance. Particularly inthe case of a high speed filling line, the fine particles of liquidnitrogen may splash back when colliding the surface of the liquidcontent so that they splash out of the container. Thus this method stilldoes not satisfy to obtain low pressurized cans that requires the smallvolume injection of liquid nitrogen with extremely high accuracy.

Therefore, an object of the present invention is to provide a method andapparatus for manufacturing a pressurized packaging body wherewithprescribed internal pressures of the pressurized packaging bodies can bestably obtained even at low internal pressure by increasing the accuracyof the initial internal pressure, and the inert gas displacement ratioin the pressurized packaging bodies can be dramatically improved overthe prior art.

A detailed object of the present invention is to provide a method andapparatus for manufacturing a pressurized packaging body, wherewithsmall volume injection of liquefied inert gas or solidified inert gascan be done precisely by stably made into fine particles, wherewith lowpressurized gas displacement packaging bodies are obtained which exhibitoutstanding guaranteed quality, and wherewith it is possible to employthin walled cans even for cans containing low acid beverages.

DISCLOSURE OF THE INVENTION

The present invention, basically, is a method wherewith a liquefiedinert gas or solidified inert gas that is to be vaporized to become aninert gas is made into fine particles, sprayed together with a lowtemperature inert gas having a temperature that is at or below the finalequilibrium temperature of the gas displacement pressurized packagingbody into the head space of a container filled with contents, andsealed, thereby displacing the gas in the head space with the inert gas,and, at the same time, causing an internal pressure to be produced bothby the vaporizing expansion of the fine particles of the remainingliquefied inert gas or the fine particles of the remaining solidifiedinert gas, and also by the thermal expansion of the said low temperatureinert gas, after sealing. Thus it is possible to obtain pressurizedpackaging bodies that exhibit high internal pressure accuracy and a highinert gas displacement ratio, whereupon the object mentioned above isattained.

The fine particles of the said liquefied inert gas can be definitelygenerated by supplying a liquefied inert gas from a liquefied inert gastank to the inlet of the orifice of the said spray nozzle withpreventing the vaporization thereof by a thermally insulated passageway,passing through the said orifice in a liquid state and discharging itinto the atmosphere, whereupon the liquefied inert gas exhibits a rapidvaporized expansion effect immediately after exiting the orifice,thereby causing the other liquefied inert gas still in the liquid phaseto be made into fine particles. Liquid nitrogen is basically adopted asthe liquefied inert gas mentioned above and dry ice as the solidifiedgas, but such are not necessarily limited thereto.

For the said low temperature inert gas, the vaporized gas generated bythe vaporization of some part of the liquefied inert gas supplied to thesaid spray nozzle under prescribed pressure is used, but that may beused in conjunction also with inert gas supplied by a separatepassageway from the inert gas supply source. In order to increase theaccuracy of injection to the inside of the container, it is preferablethat the liquefied gas be sprayed toward the opening of the containerfrom the spray nozzle so that a pattern having a spread angle of from20° to 100° is formed. When that is done, the range of spray flow volumefor the liquefied gas should be from 0.2 g/s to 4.0 g/s. If the sprayflow volume is less than 0.2 g/s, the desired internal pressure ofcontainer will not be obtained, whereas if it exceeds 4.0 g/s, pulsationreadily occurs during spraying, whereupon the spray angle will notstabilize and it will be difficult to obtain a stable spray flow. A morepreferable spray flow volume is the range of 0.2 g/s to 3.0 g/s. Here,the spray pattern means the spatial distribution of numerous fineparticles of liquid nitrogen that is formed immediately afterdischarging from the nozzle orifice. Liquid nitrogen is generally usedas the liquefied gas that is injected into the container in order tomanufacture a gas displacement pressurized packaging body, and thepresent invention can also be favorably adapted to liquid nitrogen sprayinjection.

It is preferable that the spray pattern be formed so that the horizontalcross-sectional shape thereof approximates a shape somewhere between asquare and an ellipse so that thereby the inside of the container can beinjected with the fine particles of liquefied gas efficiently. The fineparticles of the liquefied gas sprayed from the spray nozzle should havea particle diameter of 2 mm or less. When the particle diameter exceeds2 mm, it is difficult to control injection precisely just as withconventional flow-down injection.

Moreover, in order to make the liquefied gas into fine particlesefficiently and definitely, the nozzle temperature while the liquefiedgas is being sprayed should be no less than the boiling point of theliquefied gas and no more than that boiling point +75° C., andpreferably a temperature between that boiling point and the boilingpoint +50° C. When liquid nitrogen is being sprayed, for example, thenozzle temperature should be no greater than −120° C. and no less thanthe boiling point of the liquefied gas, and preferably between −150° C.and the boiling point of the liquefied gas. The spray pressure should befrom 1 kPa to 150 kPa, and preferably from 1 kPa to 30 kPa.

When the liquefied gas is being atomized, the spray nozzle should beisolated from the outside air by double purge gasses consisting of aninner purge gas at a comparatively low temperature and an outer purgegas at a comparatively high temperature. However, it is also permissibleto use only low temperature vaporized gas that is vaporized inside aliquefied gas storage tank, particularly a pressurized liquefied gasstorage tank.

It is also desirable that the liquefied gas be sprayed diagonally, at anangle of 5° to 45°, and preferable of 15° to 40°, from the vertical,with respect to the conveyance of the container, so that the liquefiedgas spray flow contains a velocity component in the direction ofcontainer conveyance. The spray distance from the tip of the spraynozzle to the contents surface of the container should be from 5 to 100mm, and preferably from 45 to 60 mm. By such means as these, it ispossible to stably obtain low pressurized packaging bodies having acontainer internal pressure of 0.2 to 0.8 kgf/cm² after sealing.

Basically, when the said container is a metal can, the said liquefiedinert gas can be sprayed to inject the can while it is being conveyedfrom the filler to the seamer. However, by settling the spray nozzle inthe seamer as a undercover gassing device, the liquefied inert gas canbe sprayed inside the container by undercover gassing method.

The apparatus for manufacturing the pressurized packaging body of thepresent invention comprises a liquefied inert gas storage tank and spraydevice that have a spray nozzle deployed so that it is connected to thebottom of that liquefied inert gas storage tank. The spray devices havevalve for controlling the liquefied inert gas flow volume, the spraynozzle having nozzle orifice, and a thermally insulated passageway forsupplying the liquefied gas from the valve to the nozzle orifice.

The means of vacuum insulating the liquefied inert gas flow passagewayor the like may be adopted for the thermally insulated passagewaymentioned above. However, said spray nozzle can be cooled and controlledthe temperature more effectively by configuring the outer circumferenceof the liquefied inert gas flow passageway from the said valve to thesaid spray nozzle by enclosing with a nozzle cooling chamber into whichthe liquefied inert gas flows from the liquefied inert gas storage tank.The structure of the spray nozzle for making the liquefied inert gasinto fine particles more definitely should have a spray nozzle tip ornozzle tips consisting of a small orifice or orifices having an openingarea of 0.15 to 4 mm² and preferably of 0.2 to 3 mm². If the openingarea in the spray nozzle orifice or orifices is smaller than that range,vaporization will occur during discharging and it will be very difficultto achieve atomization, whereas if it is larger that range, the liquiddroplets will become too large, similar to a flow-down injectionsituation, and it will become difficult to obtain fine particles.

It is desirable to deploy the said spray nozzle inclined at an angle of5° to 45°, and preferably of 15° to 40°, from the vertical downwarddirection, gives the spray flow a velocity component in the direction ofcontainer conveyance so that the fine particles of the liquefied gasimpacts softly on the liquid surface inside the container. It ispreferable that the said spray means comprise purge device forpreventing frosting by isolating at least the vicinity of the nozzleoutlets from the outside air by a purge gas. These said purge gas deviceare formed as a double purge gas hood arrangement consisting of an innerpurge gas hood forming an inner purge gas passageway and an outer purgegas hood forming an outer purge gas passageway. Moreover, the partfacing the nozzle tip of said inner purge gas hood can be configured asa spray beak by forming the said inner purge gas hood to enclose fromthe lower outer circumference part to the nozzle tip of the said spraybody. However, when the vaporized gas in the inert gas storage tank, andparticularly the vaporized gas generated from a pressurized tank, isinducted as the purge gas, it is possible to obtain low temperaturepurge gas with sufficient volume for adequate purging without formingdouble purge passageways, making the structure simpler.

Spray device is desirable to configure a spray device assembly byattaching each constituent parts so that the assembly process can besimplified. Also, by either deploying the said spray devices in aplurality along with the direction of container conveyance at the bottomof the liquefied gas storage tank, or deploying those in combinationwith liquefied gas flow-down devices to configure multiple nozzles, itis possible to decrease fluctuation relative to internal pressure and toeffect more precise injection, so that is desirable. It then alsobecomes possible to effect highly precise liquefied gas injection evenwhen the spray volume is large. If an initial purge mechanism forsupplying a dry heated gas to the inside of the liquefied gas storagetank, prior to supplying the liquefied gas, and removing moisture fromthe tank inside is connected to the liquefied gas storage tank, aninitial purge can be performed and no frost will form in the tank, sothat is desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of the basic configuration of apressurized packaging body manufacturing apparatus relating to thepresent invention;

FIG. 2 is a graph representing the relationship between splash distanceof liquid nitrogen particle resulting from rotation inside a seamer andparticle diameter;

FIG. 3 is a graph representing the relationship between the liquidcontents filling quantity and filling internal pressure in a pressurizedpackaging body;

FIGS. 4-A to 4-D are schematic diagrams of phenomena in the process ofmanufacturing a pressurized can by the pressurized packaging bodymanufacturing method of the present invention;

FIG. 5 is a section of a liquefied gas spraying injection apparatusrelating to an embodiment aspect of the present invention;

FIG. 6 is a three-dimensional section of a spray device assembly;

FIG. 7 is a bottom view of a spray nozzle viewing from the spray beakoutlet;

FIG. 8 is a chart representing the relationship between can internalpressure and liquefied gas spray flow volume;

FIG. 9 is a chart representing the relationship between can internalpressure and spray nozzle orifice area;

FIG. 10 is a schematic diagram representing the positional relationshipbetween a container and a spray nozzle;

FIG. 11 is a section of a spray pattern;

FIGS. 12-A1 and 12-A2 are a front view and bottom view of a nozzle tipin a liquefied gas spray injection apparatus relating to anotherembodiment aspect of the present invention, while FIGS. 12-B1 and 12-B2are a front view and bottom view of a nozzle tip in a liquefied gasspray injection apparatus relating to yet another embodiment aspect ofthe present invention;

FIG. 13 is a section of a liquefied gas spray injection apparatusrelating to another embodiment aspect of the present invention;

FIG. 14-A is a section of a liquefied gas spray injection apparatusrelating to yet another embodiment aspect of the present invention, andFIG. 14-B is an enlarged drawing of the main parts thereof; and

FIG. 15 is a section of a liquefied gas spray injection apparatusrelating to yet another embodiment aspect of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Before describing the embodiment aspects of the present invention, thefundamental principle of the present invention is described at first. Inthe following description, a case that is obtaining an inert gasdisplacement pressurized can by injecting liquid nitrogen into a metalcan is described as a typical example of gas displacement pressurizedpackaging body.

The reasons why internal can pressure fluctuation occurs in cans withconventional liquid nitrogen injection are {circle around (1)} that,because liquid nitrogen has an extremely low temperature (the boilingpoint thereof being −196° C.), when the liquid nitrogen injection isbeing done, the liquid nitrogen collide to the surface of the liquidcontents, whereupon a bumping phenomena occurs which produces liquiddroplets that readily splash out to the outside, which phenomena is alsoinduced by vibration during conveyance to the seamer and by the highspeed rotation and revolution of the can at the seamer, and also,because of the evaporation that occurs between injection and seaming,the volume of liquid nitrogen splashed and/or evaporated is indefiniteand the residual liquid nitrogen volume at the seaming cannot beaccurately controlled, and {circle around (2)} that the generation ofcan internal pressure after seaming in the liquid nitrogen fillingprocess results not only from the vaporization of the liquid nitrogen,but also from the thermal expansion of the low temperature vaporized gasfilling into the head space of the can along with the liquid nitrogenduring sealing, consequently the internal pressure generated as a resultof these causes is influenced by the fluctuation in the volume ofcontent packed into the container.

Thereupon, the inventors conducted research for the purpose of resolvingthe problems noted in the foregoing in {circle around (1)} and {circlearound (2)} together. As a result, they discovered that by making aliquid or solid that is to be vaporized to form an inert gas into a fineparticle and injecting that simultaneously with a low temperaturevaporized gas into the head space in the container, pressurized cansexhibiting small internal pressure fluctuation can be stably obtained,and gas displacement can be effected with a high displacement ratio. Asa result of their research, the inventors further discovered a methodand apparatus for stably and definitely atomizing liquid nitrogen, whichis difficult to atomize because of its extremely low temperature. Thusthe inventors reached the present invention.

The inventors first focused on the droplet size of liquid nitrogen,performed experiments to investigate the relationship between the liquiddroplet splash distance induced by can rotation and the diameter of theliquid droplets, and obtained the results shown in the graph in FIG. 2.The experiments represented by this figure were the case of a canrotation speed of 2500 rpm and a seaming time of 0.2 seconds. As aresult, it was found that the splash distance becomes shorter as theparticle size of the liquid droplet becomes smaller.

When the particle diameter is 1 mm, the splash distance is approximately30 mm, whereas when the particle diameter is 0.1 mm, the splash distanceis only approximately 0.3 mm, so that the splash distance is seen toincrease exponentially as the particle diameter becomes larger.Consequently from these experiments, it can be predicted that, at arotation speed of 2500 rpm, when the liquid nitrogen particle diameterexceeds 1 mm, the splash distance will be such that there will benumerous splashing out of the conventional beverage can, whereas, whenthe particle diameter is less than 1 mm, there will be almost nosplashing out of the can. It was hence understood that atomizing theliquid droplets, making their particle diameter small, is extremelyeffective in preventing the liquid nitrogen from splashing out to theoutside of the can. The reason why the liquid nitrogen splash distancedecreases when the liquid droplets are atomized is thought that, afteratomization, the effects of viscosity become predominant over theeffects of inertia, so that splashing ceases.

The following experiments were also conducted to investigate the effectsof fluctuation of contents volume on can internal pressure.

Liquid contents are filled into a container having a full capacity of370 ml with a range of from 340 g to 350 g varying at 1 g step, andchanges in can internal pressure were measured, after injecting fineparticles of liquid nitrogen and low temperature nitrogen gassimultaneously into the container and then sealing. For a comparativeexample, the same experiments were performed after injecting byconventional liquid nitrogen injection method and after injecting onlylow temperature gaseous nitrogen. The experimental results are shown inFIG. 3. In FIG. 3, curve a represents the case where injection was donewith fine particles of liquid nitrogen and with gas vaporized therefrom(low temperature gas), curve b the case where only liquid nitrogen wasinjected, and curve c the case where only low temperature gaseousnitrogen was injected. Curve d represents the case of hot pack filling.As is evident from FIG. 3, filling internal pressure contributed withliquid nitrogen vaporization expansion increases as the contents volumeincreases, as indicated by curve b, whereas the filling internalpressure contributed with the thermal expansion of low temperaturegaseous nitrogen decreases, as indicated by curve c. From this it isunderstood that, by mixing these together in a suitable ratio, it ispossible to maintain the filling internal pressure constant,irrespective of fluctuation of the contents volume, as indicated bycurve a.

From these experimental results noted above, it will be understood thatthe absolute value of the filling internal pressure can be set to anydesired value by selecting the volume of liquid nitrogen and thetemperature of the gaseous nitrogen, that the filling internal pressurecan be controlled, and that pressurized cans which exhibit smallfluctuation in internal pressure can be obtained.

Moreover, as a result of various kinds of experiments on methods foratomizing liquid nitrogen definitely, the inventors discovered aphenomenon whereby, by forming the nozzle orifice very small, settingthe physical conditions such as pressure, flow volume, and nozzletemperature so that the liquid nitrogen passes quickly through theorifice in a liquid state, and discharging the liquid nitrogen from theorifice or orifices into the atmosphere, some of the discharged liquidnitrogen vaporize and expand rapidly, and atomize the rest of the liquidnitrogen that is in a liquid phase. The present invention is based onthese findings.

FIG. 1 is a simplified diagram of an embodiment aspect of a gasdisplacement pressurized packaging body manufacturing apparatus forachieving the subjects mentioned above. This embodiment aspect has asingle nozzle that is connected to a liquid nitrogen supply mechanism,sprays the liquid nitrogen fine particles and low temperature gaseousnitrogen to inside of a can from that nozzle.

In FIG. 1, symbol 50 is a nozzle body, which nozzle body has a nozzletip 51 comprising a very small orifice or orifices. About the peripherythereof are deployed simple thermal insulation devices 52 formed by airinsulation and/or thermal insulation material or the like. In order toform the liquid nitrogen into a good mist by the vaporization expansioneffect, the inner wall temperature of the nozzle orifice must bemaintained so that the liquid nitrogen does not boil while passingthrough the nozzle orifice, and so that a portion of the liquid nitrogenvaporizes and expands immediately after passing through the nozzleorifice and being discharged into the atmosphere (the boiling pointcorresponding to the pressure inside the pipeline is preferable). Tosatisfy these temperature conditions, the inflow of heat from theoutside is controlled by the said simple thermal insulation device.

The spray nozzle 50 is connected to a liquid nitrogen supply mechanismthat includes a liquid nitrogen supply tank 53. More specifically, thespray nozzle 50, via a pipeline 54, is connected to the liquid nitrogensupply tank 53 that has a thermally insulated vacuum structure, and aflow volume regulating valve 56 is deployed at an intermediate point inthe pipeline. The pipeline 54 has a structure that insulates the heatinvasion from the outside so that the liquid nitrogen can be suppliedfrom the liquid nitrogen supply tank 53 to the spray nozzle 50 withoutbeing vaporized, by enclosing with vacuum devices 57 to the spray nozzle50 including each valves. To the vapor phase part of the liquid nitrogensupply tank 53, through a pipeline 59, is connected a pressurized gascylinder 58 deployed on the outside. A pressure regulating valve 60 isdeployed at an intermediate point in that pipeline 59. Thus, bysupplying pressurized gas to the liquid nitrogen supply tank, thepressure inside the tank can be increased. Furthermore, on the vaporphase part of the liquid nitrogen supply tank, a pipeline 61 that opensto the outside is connected, via a pressure regulating valve 62, so thatgas inside the tank can be released to the outside when the pressureinside the liquid nitrogen supply tank exceeds a set value. Said valvesare controlled by a control unit 63, to supply the spray nozzle withliquid nitrogen at the desired pressure and flow volume. Byappropriately controlling the pressure and flow volume of the liquidnitrogen discharged from the nozzle orifice 51 which changes the liquidnitrogen vaporization ratio and the fine particle formation ratio, it ispossible to control the low temperature nitrogen gas volume and theliquid nitrogen fine particle volume injected into the container.

The gas displacement pressurized packaging body manufacturing apparatusof this embodiment aspect is configured as described above, the pressureregulating valves and flow volume regulating valves are operatedaccording to commands from the control unit 63, the internal pressure,liquid volume, and so forth in the liquid nitrogen supply tank 53 arecontrolled to set values, and obtains the discharge pressures and flowvolumes of the liquid nitrogen discharged from the nozzle orifice 51which satisfy the desired physical conditions. As a result, a part ofthe liquid nitrogen discharged from the spray nozzle 50 is vaporized,the liquid nitrogen still in the liquid phase is atomized by thevaporizing expansion thereof, and both low temperature nitrogen gas andfine particles of liquid nitrogen are produced. It is therefore possibleto inject both fine particles of the liquid nitrogen and low temperaturenitrogen gas into the container simultaneously from a single nozzle. Atthat time, the gasification rate of the liquid nitrogen as it vaporizesand the atomization rate thereof can be controlled by controlling saiddischarge pressure and flow volume so that the mass of liquid nitrogenatomized is from 15% to 60% of the total volume of liquid nitrogensprayed, whereby the prescribed internal pressure and gas displacementin the container headspace after sealing can be obtained. In order toincrease the gas displacement ratio, the liquid nitrogen vaporizationratio should be within the range noted above (that is, from 40 to 85 wt.% of the liquid nitrogen).

The operating processes of the gas displacement, by injecting fineparticles of liquid nitrogen and gaseous nitrogen into a can, asdescribed above, are represented in schematic form in FIGS. 4-A to 4-D.As shown in FIG. 4-A, by injecting a mixture of fine particles of liquidnitrogen having the prescribed particle diameter and gaseous nitrogen(hereinafter called the mixture gas for convenience) into headspace, airis expelled from the headspace and replaced by nitrogen. Unlikeconventional cases where liquid nitrogen is simply flow down, liquidnitrogen that has been atomized and low temperature gaseous nitrogenthat has been vaporized are blown simultaneously, wherefore inject andspread over the headspace with the state of mixture gas. In FIG. 4, thearrows a represent the blowing aspects of the mixture gas toward thecan, the symbol 65 indicates the mixture gas that has been replaced withair inside the head space, and the arrows b indicate the flow of thatair. The container displaced with gas is conveyed to the seamer whereseaming is conducted. While being conveyed, the fine particles of liquidnitrogen are vaporized and expand, as indicated in FIGS. 4-B and 4-C,wherefore, due to the pressure increase of that expansion, a flow ofnitrogen gas from the inside of the can to the outside (indicated by thearrows c) is generated and the invasion of air into the can isprevented. In FIG. 4-B, the arrows d indicate the flow of air.. At theseamer, the can is turned by revolution and rotation movements. However,because the liquid nitrogen fine particles are governed more by theeffects of viscosity than the effects of inertia, the fine particles ofliquid nitrogen do not splash out to the outside despite the effects ofthe turning movements (cf. FIG. 4-C). While the vaporizing expansion ofthe liquid nitrogen fine particles is going on, the lid 66 is set inplace and seaming is performed to effect sealing (cf. FIG. 4-D),whereupon an internal pressure is generated by the vaporizing expansionof the remaining liquid droplets and by the thermal expansion of the lowtemperature gas after sealing, resulting in a pressurized can. In FIG.4, the can is indicated by the symbol 67 and the liquid content by thesymbol 68.

The concrete mechanisms from the liquid nitrogen supply tank to thespray nozzle in said embodiment aspect are described in FIGS. 5 to 7.

A section thereof is shown in FIG. 5. A three-dimensional section of thespray device assembly is shown in FIG. 6. In these figures, symbol 1 isa liquefied gas (liquid nitrogen) storage tank formed in a double walledthermally isolated vacuum structure having a thermally insulated vacuumvessel (hereinafter called simply the tank), which corresponds to theliquid nitrogen supply tank of the said embodiment aspect. The spraydevices for atomizing and spraying the liquid nitrogen are deployed inthe open part of the bottom part thereof. The spray devices consist of avalve 2 for controlling the liquid nitrogen flow volume (correspondingto the flow volume regulating valve in the said embodiment aspect) and aspray nozzle 3 (hereinafter called simply the nozzle), in terms of basicconfiguration thereof. In terms of an additional configuration fordefinitely atomizing and spraying the liquid nitrogen, there are aliquid nitrogen flow passageway 4 reaching from the valve 2 to thenozzle 3, a nozzle cooling vessel 5 for cooling that flow passageway,and purge devices for isolating the outer peripheral part anddischarging part of the nozzle from the outside air to prevent frosting.In this embodiment aspect, as shown in the three-dimensional section ofFIG. 6, these components are attached integrally to a spray body 6 toconfigure a spray device assembly 10.

The spray body 6, as shown in FIG. 6, has a cylindrical outer wall 11that has inner diameter matching with an opening formed in the bottomwall of the tank 1, and is provided with a pipe 13 uprightly, passingthrough that bottom wall 12, to configure a liquid nitrogen passageway.Accordingly, the cylindrical outer wall 11 of the spray body and thepipe 13 form a double structure, and the nozzle cooling vessel 5 intowhich liquid nitrogen flows from the tank 1 is configured between thecylindrical outer wall 11 and the pipe 13. As shown in a figure, saidnozzle cooling vessel 5 extends to the vicinity of the nozzle, cools thepipe 13 and the nozzle 3 continually by the liquid nitrogen. Thus it ispossible to supply liquid nitrogen to the nozzle, without boiling orvaporization from the tank to the nozzle, but while also imparting atemperature gradient up to near the boiling point thereof.

The opening at the upper end of the pipe 13 faces toward the opening inthe tank 1, and a valve seat 14 of the valve 2 that controls the supplyof liquid nitrogen to the nozzle is provided in that opening. The valve2 is configured by a needle valve, having a valve rod 15 that is capableof up-and-down motion relative to the valve seat 14 passing through theinside of the tank and protruding from the top thereof, and capable ofdrive control from outside by unshown valve control device. At the upperend of the pipe 13 is deployed a bubble deflection component 16,positioned above the valve seat 14. This bubble deflection component 16precludes the incursion of bubble into the pipe 13 even the liquidnitrogen in the nozzle cooling vessel 5 vaporize, and precludes theincursion of the bubble into the nozzle that would impair theatomization of the liquid nitrogen.

As shown in FIG. 5, the lower end of the pipe 13 is formed on inclinedsurface so that the direction of spray inclines by an angle of α fromvertically downward, and the nozzle 3 is fixed on said inclined surfaceinclined by the angle α from the horizontal. The inclination angle α isselected within a range of 5° to 45° for reasons explained subsequently.The nozzle 3 is configured by a nozzle tip 17 and a holding mouth piece18 that fixing the nozzle tip to the spray body. The nozzle tip 17 has achannel 19 formed in the center of the lower end thereof which isperpendicular to the direction of container conveyance. In the center ofthis nozzle tip 17 is formed a nozzle orifice 20 consisting of a narrowhole that connects with the liquid nitrogen flow passageway. The holdingmouth piece 18 has an opening that is sufficiently larger than thenozzle orifice 20. Because the nozzle 3 has the structure describedabove, the liquid nitrogen sprayed from said nozzle is formed a flatspray pattern that is somewhere between a square and elliptical shape asa whole, having a prescribed spread angle, and sprayed diagonally sothat having a velocity component in the direction of can conveyance. Thespread angle of the spray pattern is influenced by the shape of thenozzle tip and the spray pressure. In this embodiment aspect, however,the spray spread angle is appropriately selected within a range of 20°to 100°, as describe later.

purge devices are deployed at the outer periphery of the spray body 6.The purge gas is needed only a dry gas that contains no component thatwill be frozen by the liquid nitrogen (moisture or the like), and thisgas preferably should be nitrogen or dry air. If the purge gas flow istoo small, the atmospheric air will not be thoroughly purged, andfrosting will occur on the nozzle. If the purge gas flow is too large,on the other hand, stable spraying of the liquid nitrogen will beimpaired, leading to a decrease in the spray flow volume and to anincrease in fluctuation therein. Furthermore, if the purge gastemperature is too high, the nozzle and liquid nitrogen spray flow willbe heated, leading similarly to a decrease in the spray flow volume andto an increase in fluctuation therein. Accordingly, although it isdesirable that the purge gas temperature be lower than atmospherictemperature in the interest of good liquid nitrogen spraying, theoutermost layer of the apparatus is in contact with atmospheric air atroom temperature, wherefore, in order to prevent condensation orfrosting, this part of the apparatus should not be excessively cooled.

From this point of view, in this embodiment aspect, the purge gas flowpassageway is formed doubly as an inner purge gas passageway 21 and anouter purge gas passageway 22, in a configuration wherein relative lowtemperature inner purge gas flows in the inner purge gas passageway 21,and relatively high temperature purge gas flows in the outer purgepassageway 22. In the drawings, symbol 23 is an inner purge gas hoodthat forms the inner purge gas passageway between itself and the spraybody, formed such that the nozzle tip is enclosed from the lower outerperiphery of the spray body, and forming a spray beak at the placefacing the nozzle tip. A spray guide port 25 in the spray beak has ashape that corresponds to the spray pattern. In this embodiment aspect,as shown in FIG. 5 and FIG. 6, this spray guide port 25 is formed as anflat ellipse cross section with a prescribed spread angle from the upperend thereof, so that an overall flat elliptical shape is formed havingthe long diameter in a direction perpendicular to the direction ofcontainer conveyance at the outlet end thereof. The said spread angle isselected according to the container to be injected with liquid nitrogen,within a range of 20° to 100°. It should be noted that FIG. 7 shows theview of the spray nozzle in the direction of the arrow B from below thespray device assembly 10 in FIG. 5, to help the understanding. Symbol24, moreover, is an opening at the upper end of the spray guide port 25,opened so as to face the spray nozzle.

At the outer periphery of the inner purge hood 23 is fixed an outerpurge hood 26 that forms the outer purge gas passageway 22 betweenitself and that outer periphery. To the outer peripheral part of thatouter purge hood 26, a protective mouth piece 28 having a cylindricalouter periphery is attached integrally thereto, a heater 27 is deployedbetween that protective mouth piece and the outer purge hood, so thatthe outer purge hood can be heated on demand to prevent condensation andfrosting. In the figure, symbol 29 is an inner purge gas supply linewhich, in this embodiment aspect, is connected to the gas phase portionof the tank, and the vaporized gas inside the tank is used as the innerpurge gas. Symbol 30 is an outer purge gas supply line which isconnected to an external nitrogen gas tank. Symbol 31 is a tank cover.

Although not shown in the drawings, a liquid surface level sensor formeasuring the level of the liquid surface of the liquid nitrogen 33stored therein, a gas exhaust line for releasing vaporized gas that hasvaporized in the tank to the atmosphere to maintain a constant pressurein the tank, and a pressurized line for inducting pressurized gas intothe tank from the outside to control the internal gas pressure, via apressure regulating valve are connected to the tank 1. The spraypressure can be controlled by suitably controlling the liquid surfacelevel, the gas exhaust volume, and the pressurized gas volume. Also, aninitial purge mechanism is provided for sterilizing the inside of tankand completely removing moisture therefrom prior to the storage ofnitrogen gas inside the tank. Said initial purge mechanism comprises,for example, mechanisms for supplying steam for steam-sterilizing theinside of the tank and for supplying heated inert gas or heated air fordrying the inside of the tank after the steam sterilization.

The liquid nitrogen spray injecting apparatus in this embodiment aspectis configured as described above, and a liquid nitrogen flow passagewayis formed from the tank 1 to the nozzle orifice 20 of the nozzle tip 17via the opening in the bottom of the tank, the valve seat 14, and thepipe 13. The pipe 13 has its outer periphery cooled by liquid nitrogen,and the inflow of heat from the outside is blocked, wherefore the liquidnitrogen flow passageway from the tank 1 to the nozzle orifice 20becomes a thermally insulated passageway. Unlike the tank, however, thisis not a completely thermally insulated structure, wherefore the inflowof the heat of the outside air to the spray body 6 and nozzle tip 17 isnot completely blocked, and the liquid nitrogen passing through the pipe13 is affected by that heat inflow so that its temperature graduallyincreases, wherefore a temperature gradient develops. By using thistemperature gradient, it is possible to increase the temperature of theliquid nitrogen passing through the nozzle orifice 20 to near theboiling point at the spray pressure, and the liquid nitrogen dischargedfrom the nozzle orifice 20 can be effectively atomized.

Meanwhile, to accurately inject a prescribed volume of liquid nitrogenat a cryogenic temperature to inside of the container, both stableliquid nitrogen spraying and proper injecting of the sprayed liquidnitrogen to the inside of the container are required. In the presentinvention, various investigations were made for nozzle temperatures,nozzle orifice diameters, spray pressures, and spray flow volumes, etc.,as spray conditions for achieving proper stabilized liquid nitrogenspraying, and investigations were also made concerning spray patterns,sprayed particle sizes, spray angles, and spray distances, in terms ofconditions for proper injection of the sprayed liquid nitrogen to theinside of the container.

The spray pattern is influenced by spray flow volume and spray spreadangle, and is also influenced by the particle diameter of the sprayedliquid nitrogen. The can internal pressure at the filling process isrelated to the spray flow volume (that is, to the injecting volume intothe can), and the spray flow volume is determined by the spray pressureand the area of the orifice in the nozzle tip. Therefore, in order toincrease the can internal pressure at the filling process, the nozzleorifice diameter must be large, and/or the spray pressure must beincreased. However, when the nozzle orifice diameter is large, thediameter of the liquid droplets also becomes large, and a phenomenonoccurs whereby those liquid droplets are submerged in the liquidcontents and bumping. And the effects of the fluctuation of can internalpressure according to the number of liquid droplets entering the liquidcontents and of the fluctuation induced by liquid droplet splashingbecome great, and the precision of the can internal pressure at thefilling process deteriorates. Thereupon, with the cans which were filledwith 240 g of water at a temperature of 65° C., and, while conveyingthem at a line speed of 1500 cpm, the relationship between the caninternal pressure and the liquid nitrogen spray flow volume per unittime was investigated. The liquid nitrogen spray flow volume wasmeasured by collecting liquid nitrogen sprayed from the nozzle on abalance scale having a container filled with liquid nitrogen placed onthe pan thereof, and measuring the amount of weight increase per unittime. The results are plotted in FIG. 8.

FIG. 8 shows the relationship between can internal pressure and liquidnitrogen spray flow volume when the spray pressures are 1 kPa, 5 kPa,and 10 kPa. As is clear from this figure, at every spray pressure,fluctuation in can internal pressure gradually increased as the sprayflow volume increased, and became quite large when spray flow volumeexceeded 4.0 g/s. If the spray flow volume is low, conversely, thefluctuation in can internal pressure decreases. When this falls to orbelow 0.2 g/s, however, the desired can internal pressure cannot beobtained. Therefore the spray flow volume should be within a range of0.2 g/s to 4.0 g/s, and preferably within a range of 0.2 g/s to 3.0 g/s.

The relationship between the nozzle orifice area and the liquid nitrogenspray volume was investigated, at the spray pressures above, namely 1kPa, 5 kPa, and 10 kPa, varying the nozzle orifice area of a nozzle ofthe type of said embodiment aspect within a range of 0.1 to 4 mm², andmeasuring the liquid nitrogen spray flow volume for each nozzle orificearea. As a result, as indicated in the graph in FIG. 9, it was observedthat there is a strong correlation between nozzle orifice area and sprayflow volume, and that a spray flow volume of 0.2 g/s to 4.0 g/s can beobtained by making the nozzle orifice area to be within a range of 0.15to 4.0 mm². When the orifice area is 4 mm², it is very difficult toobtain a flow volume lower than 2.0 g/s. Therefore, in order todefinitely obtain a spray flow volume of 0.2 g/s to 3.0 g/s, the nozzleorifice area should be selected within the range of 0.2 to 3 mm².

As shown in FIG. 10, in the case of spraying, the fine particles ofliquid nitrogen spread out and are distributed in space, wherefore,unlike the case of flow-down in a stream shape, the fine particles ofthe liquid nitrogen is injected across the entire area of the opening inthe can, or at least across a wide range thereof. As a result,evaporation of the liquid nitrogen occurs over a wide range of theinjected liquid surface, whereupon oxygen elimination effect isadvantageously enhanced as compared to flow-down method. That spreadangle β (cf. FIG. 10) is determined by the shape of the nozzle tip 17and the spray pressure. When the spread angle β is large, the fineparticles spread across a wide range of the opening, but, if the fineparticles are distributed across too wide, some will spill outside thecan opening, and efficiency will deteriorate. Accordingly, the spreadangle range of spraying should be from 20° to 100° in the case thatcontainer is can. When the spread angle is below 20°, spraying becomes anearly flow-down aspect, and said advantage is not in effect. The sprayspread angle is affected by the diameter of the container opening andthe spray distance. When the actual spray distance is between 35 and 65mm and the container opening diameter is 50 mm, for example, a spreadangle range of 71° to 42° was found to be preferable, and in the case ofa container opening diameter of 60 mm, a spread angle of 86° to 54° wasfound to be preferable.

The spray pressure, in this embodiment aspect, is controlled bymeasuring the pressure in the tank, and adding thereto the head pressurecalculated from the height of the liquid surface from the spray orifice.That is, the spray pressure is thought of as the sum of the spontaneouspressure caused by liquid nitrogen evaporation, the pressure applied tothe tank from the outside, and the head pressure generated by the weightof the liquid nitrogen itself. It is necessary that spray pressure isapplied in order to create fine particles of the liquid nitrogen.However, when the spray pressure is too high, excessive liquid nitrogenvaporization occurs due to the rise in the boiling point, andsatisfactory spray state are not realized. On the other hand, when thetank internal pressure is too high, a liquid supply from the liquidnitrogen supply source becomes difficult, particularly in cases wherethe supply of liquid nitrogen is taken from a gas-liquid separator. Inview of these facts, the spray pressure range should be from 1 kPa to150 kPa, and preferably from 1 kPa to 30 kPa in cases where a gas-liquidseparator of open to the atmosphere type is used.

It is to be noted further that the size of the fine particles of liquidnitrogen formed by spraying need not necessarily constitute extremelyfine particles in a fog or mist form. It is necessary only thatconditions be satisfied so that there be no splashing of liquid dropletsdue to impact with the liquid surface at injection and that a prescribedquantity thereof remain as liquid nitrogen inside the container.Experiments demonstrated that those conditions was satisfied if the sizeof the fine particles formed by spraying was 2 mm or smaller, and thatthere was not different from conventional flow-down injection when thatsize exceeded 2 mm. It was further found that the fine particles havingan average fine particle diameter of 1 mm or smaller is preferablysatisfied said conditions more effectively.

Liquid nitrogen can be atomized well with conditions setting asdescribed above. In this embodiment aspect, the liquid nitrogen sprayangle and spray distance were further studied in the interest ofinjecting the sprayed liquid nitrogen fine particles more accurately tothe containers. First, an innovation was devised so that the fineparticles of liquid nitrogen sprayed from the nozzle could be impactingthe liquid content surface softly, injecting into a container definitelywithout splashing upon arrival at the liquid surface of the container.As technical means to that end, the nozzle tip 17 was deployed so thatit was inclined by the spray angle β relative to the direction ofcontainer conveyance, to incline the liquid nitrogen spray directiontoward the direction of container conveyance so as to impart a velocitycomponent in the direction of container conveyance to the spray flow, asshown in FIG. 5. When optimum values of the spray angle were studied, aspray angle of 5° to 45° was found to be suitable. When the spray angleis over 45°, the flight distance of the liquid nitrogen fine particlesbecomes long, whereupon the quantity of liquid nitrogen evaporatingbecomes great and the spray flow sometimes spills outside the container.When the spray angle is below 5°, it was observed that there was littlesoft impact effect. The said effects were enhanced when the spray anglewas within a range of 15° to 40°, wherefore that is a more desirablerange.

Looking next at spray distance, when the nozzle tip are brought closerto the filling liquid surface, the fluctuation in can internal pressurerelative to the spray distance becomes larger and filling internalpressure precision declines. When the spray distance is made greater, onthe other hand, there is spillage outside the can and the fillinginternal pressure declines. Evaporation in the atmosphere also has aninfluence. Accordingly, in the region therebetween, there is a regionwhere the can internal pressure does not fluctuate with distance. Whenthis fact was demonstrated by experiments, it was possible to adopt arange of 5 to 100 mm for the spray distance, but the results also showedthat a range of 45 to 60 mm is preferable because therein there isalmost no change in can internal pressure.

In the embodiment aspect above, the description relates to the case ofspray injection with a single spray nozzle. However, although the sprayvolume can be increased by simply enlarging the nozzle orifice diameter,it becomes very difficult to form fine particles once the nozzle orificearea exceeds a range of 0.15 to 4.0 mm², wherefore there is a limit toenlarge the nozzle orifice diameter. In order to overcome this problem,it is good to deploy a plural spray devices on a single tank. Byconfiguring in that way, the atomized liquid nitrogen can besequentially injected into the containers moving beneath the sprayinjection apparatus by the plural spray devices, and it becomes possibleto inject a large quantity of liquid nitrogen fine particles. Even incases where the spray flow volume is not large, by deploying a pluralspray nozzles, and performing the injection by dividing a prescribedinjecting volume between the plural spray nozzles, for example,fluctuation in injecting volume can be more effectively suppressed thanwhen injecting with a single nozzle, making this configurationpreferable for high speed production lines.

There are other means for making the spray volume larger, namely amethod wherewith a plural nozzle orifices is formed in a single spraynozzle. FIG. 12 shows nozzle tips wherein a plural (two) nozzle orificesare provided. In the nozzle tip 36 shown in FIGS. 12-A1 and 12-A2, twochannels 39 are formed in the lower end of a spray guide port 38 formedso as to protrude in a roughly rectangular shape in the center portionof a body 37. Spray outlet 41 wherein are formed nozzle orifices 40consisting of roughly rectangular shaped fine holes are provided in thecenter of each channel so that the said nozzle orifices areperpendicular to the channels 39.

The nozzle tip 43 shown in FIGS. 12-B1 and 12-B2 has a single channel 46formed at the lower end of a spray guide port 45 formed in the center ofa body 44. A spray outlet 48 wherein two nozzle orifices 47 consistingof roughly rectangular fine holes are formed in the center of thechannel is deployed so that the nozzle orifices 47 are perpendicular tothe channel 46.

In these nozzle tips 36 and 43, the nozzle orifices 40 and 47 that,respectively, are provided in a plurality, have fine holes formedtherein having opening areas within the said range, wherefore the liquidnitrogen can be sprayed well. Thus, by forming a plural nozzle orifices,the spray flow volume can be made greater than a single spray nozzle,wherefore the structure is simpler than when a plurality of spraynozzles is deployed, making it possible to lower manufacturing costs.

In the embodiment aspects described above, the description is for caseswhere a pressurized packaging body is manufactured with good internalpressure precision by merely spray injection of liquid nitrogen.Depending on the container type, however, spray injection may becombined with a flow-down injection apparatus. In a line formanufacturing canned beverages, for example, the line speed is generallyfast at 100 m/min. (1200 cpm), and it is necessary to make the liquidnitrogen spray volume large in order to obtain the prescribed containerinternal pressure on such a high speed filling line. In such cases, asdescribed above, either a plural spray devices may be deployed, or aspray nozzle having a plural nozzle orifices may be adopted, or,alternatively, a combination of both methods may be adopted to make thespray volume large. However, by combining a flow-down nozzle with aspray nozzle, and injecting most of the required liquid nitrogen volumefrom the flow-down nozzle, the deficient portion may be injected fromthe spray nozzle, making it possible to perform good liquid nitrogenspraying without making the spray flow volume large, and thus to obtaincanned goods exhibiting good internal pressure precision. In that case,the liquid nitrogen storage tank may be divided into two storage tanks,one storage tank being made open to the atmosphere, the other storagetank being made a pressured storage tank wherein the internal pressurecan be controlled, with a flow-down nozzle provided for the storage tankopen to the atmosphere, and a spray nozzle provided for the pressurizedstorage tank.

Even without dividing the liquid nitrogen storage tank into two storagetanks, however, it is possible to provide a liquid nitrogen storage tankconsisting of single pressurized storage tank with both a flow-downnozzle and a spray nozzle. In that case, it has an advantage that thetank structure is simple. FIG. 13 shows an embodiment aspect whereinboth spray nozzles and a flow-down nozzle are provided on a liquidnitrogen storage tank consisting of a single pressurized tank.

In FIG. 13, symbol 70 is a hermetic (pressurized) liquefied gas storagetank consisting of single tank that is thermally insulated by vacuum. Inthe bottom thereof are deployed two spray nozzle assemblies 71 and oneflow-down nozzle assembly 72. The spray nozzle assemblies 71 and thespray mechanism differ from the embodiment aspect shown in FIG. 5 andFIG. 6 only with respect to the purge devices, being the same in otherrespects, wherefore the same parts are indicated by the same symbols andno further description thereof is given here; only the points ofdifference are described.

In the purge devices in the spray devices of this embodiment aspect, thepurge gas hood is formed singly instead of doubly, and the purge gas isinducted from the vapor phase portion 73 of a liquefied gas storage tank70 that is hermetic and pressurized. In FIG. 13, symbol 74 is a purgehood that encloses the outer periphery of a spray nozzle 3 to form apurge gas passage 75. The purge gas passage 75 is connected to the vaporphase portion 73 of the liquefied gas storage tank 70 via a purge gassupply line 76. The purge gas is made to be inducted from the vaporphase portion of a pressurized tank, wherefore a large volume of lowtemperature liquefied gas can be obtained, and purging can be performedthoroughly without inducting outer purge gas separately from theoutside. Hence in this embodiment aspect, no outer purge gas passage isprovided to simplify the structure. A heater 77 is also deployed at theouter periphery of the spray device assemblies. When there is a dangerof dew condensation or freezing, that heater can be activated to preventdew condensation and freezing.

The flow-down nozzle assembly 72 in this embodiment aspect is aconventional type. By drive controlling a valve stem 78 in a needlevalve with an aperture drive control unit 79, appropriate volume ofliquid nitrogen can be made to flow down or drop down. Although in thisembodiment aspect, two spray nozzle assemblies 71 and one flow-downnozzle assembly 72 are deployed, the numbers thereof can be alteredvoluntarily as required.

This embodiment aspect is configured as described above. When it isnecessary to inject large quantities of liquid nitrogen, the volume ofliquid nitrogen injected into each container can easily be controlled byperforming liquid nitrogen flow-down injection with the flow-down nozzle(or nozzles), and then injecting fine particles of liquid nitrogen withthe spray nozzle (or nozzles). However, the apparatus of this embodimentaspect is not necessarily limited to applications wherein both aflow-down nozzle and a spray nozzle are used together. If the flow-downnozzle is left closed, for example, the apparatus can be used as aliquid nitrogen spray apparatus wherein only the spray nozzle or nozzlesare used, whereas if the spray apparatus valve is left closed, theapparatus can be used as a liquid nitrogen flow-down apparatus. Thus anadvantage is afforded in that one apparatus can be used for both sprayinjection and flow-down injection.

The embodiment aspect described above is such that basically a portionof liquid nitrogen discharged from a spray nozzle very rapidly expandsas it vaporizes, while other liquid nitrogen in the liquid phase isatomized into fine droplets, and, based on that phenomenon, the gas inthe headspace of the container is displaced by an inert gas, that beingonly the low temperature vaporized gas resulting from the partialvaporizing expansion of the liquid nitrogen. However, an inert gas mayalso be supplied simultaneously from inert gas supply devices providedseparately.

FIGS. 14-A and 14-B are conceptual drawings of the embodiment aspect inthat case.

In FIG. 14, symbol 91 is a spray device assembly for discharging a flowof small particle liquid nitrogen and low temperature nitrogen gas. Aspray nozzle 92 is deployed in the center part of an inert gas supplynozzle 93. As shown in the figure, the configuration is made so thatliquid nitrogen fine particles are sprayed out from the center part, andso that low temperature gaseous nitrogen is blown into the cans so as toenclose the periphery of that spray. The spray nozzle 92 is made so thatit is connected through a pipeline 96 to the liquid nitrogen supply tank95, and, a pressure regulating valve 97 and a flow volume regulatingvalve 98 are deployed intermediately in that pipeline, so that, bycontrolling these valves by a control unit 99, the particle diameter ofthe liquid nitrogen fine particles, as well as the supply pressure andflow volume therefore, can be controlled. The inert gas supply nozzle93, on the other hand, is connected to a gaseous nitrogen supplymechanism 100 by a pipeline 101, and intermediately along that pipeline101 are deployed a gas temperature control mechanism 102, a pressureregulating valve 103, and a flow volume regulating valve 104. Thepressure regulating valve and the flow volume regulating valve arerespectively controlled by the said control unit 99, whereupon thepressure and flow volume of the gaseous nitrogen blown from the inertgas supply nozzle can be controlled as desired. The pipeline to thespray assembly 91 is a thermally insulated pipeline as indicated by thedotted line 108.

With the gas displacement apparatus of this embodiment aspect configuredas described above, by establishing the nozzle orifice shape in thespray nozzle, and the fluid pressure and flow volume of the liquidnitrogen as prescribed, liquid nitrogen fine particles having theprescribed particle diameter are blown from the spray nozzle, and,furthermore, gaseous nitrogen 106 is blown from the inert gas supplynozzle so as to enclose the liquid nitrogen fine particles 109, suchthat both liquid nitrogen fine particles and gaseous nitrogen aresupplied simultaneously inside the headspace of the can 67 being carriedalong by a conveyor 110. When this is being done, the temperature of thegaseous nitrogen 106 being blown from the inert gas supply nozzle 93 iscontrolled to a low temperature by the gas temperature control mechanism102. That temperature is set, for example −150° C. or above, so that itis higher than the temperature of the evaporated gas 105 that is a lowtemperature gas generated by the evaporation of a portion of the liquidnitrogen fine particles 109 blown in fine particles.

The temperature of the gaseous nitrogen need only be a temperature atwhich thermal expansion occurs after injecting and sealing,theoretically needing only to be a temperature that is lower than thefinal equilibrium temperature. The final equilibrium temperature is theambient temperature at the application site, which will ordinarily beroom temperature. This will change depending on the applicationconditions, however. In the case where storage is done in an automaticvending machine, for example, that might be 5° C. at low temperature(refrigeration) and 70° C. at high temperature (heating), and in caseswhere used for frozen food products would be below zero.

FIG. 15 shows another embodiment aspect of the present invention. Inthis embodiment aspect, a conventional undercover gassing apparatus ismodified. A mixture gas of liquid nitrogen fine particles and gaseousnitrogen is blown into the can in an effort to simultaneously impart aninternal pressure and perform a nitrogen displacement operation in thecans by the undercover gassing method.

In FIG. 15, symbol 130 is an undercover gassing mechanism correspondingto a conventional undercover gassing apparatus. Symbol 131 is an inertgas supply nozzle that blows gaseous nitrogen, having a spray nozzle 132deployed in the center part thereof The inert gas supply nozzle 131 andthe spray nozzle 132 are connected to a gaseous nitrogen supplymechanism and a liquid nitrogen supply tank, respectively, as in theembodiment aspects described above. Because these are the same as in thesaid embodiment aspects, mechanisms that are identical to those in thesaid embodiment aspects are indicated by identical symbols, and nodetailed description thereof is given here.

In the gas displacement pressurized can manufacturing apparatus of thisembodiment aspect, configured as described above, the cans that aretransported by conveyor and reach a seamer 129 are transferred from theconveyor onto a lifter table 133, whereupon liquid nitrogen fineparticles and gaseous nitrogen are simultaneously blown into theheadspace of t he cans by the undercover gassing mechanism 130. Thus gasdisplacement is performed, in the same manner as in the embodimentaspects described above, with the mixture gas injecting the headspaceand removing air from that headspace. Then, by immediately performingseaming and sealing, internal pressure is generated by the vaporizingexpansion of the liquid nitrogen fine particles and the thermalexpansion of the low temperature gas, yielding pressurized cans thatexhibit a high gas displacement ratio and that have the prescribedinternal pressure.

Various embodiment aspects of the present invention are described above,but the present invention is not limited to those embodiment aspects butis rather amendable to various design modifications within the scope ofthe technological concept thereof. For the liquefied inert gas, forexample, instead of liquid nitrogen, either carbon dioxide gas, argongas, or a gas that is a mixture thereof may be adopted. It is alsopossible to employ dry ice instead of a liquefied inert gas. Nor is themethod of manufacturing the gas displacement pressurized packaging bodyof the present invention limited to cases where the packaging body is acan. That pressurized packaging body may be any container that can besealed and is capable of maintaining an internal pressure. Thusapplication is possible to plastic bottles, molded containers,containers made of soft materials, and glass bottles, etc. Nor is thecontent thereof limited to liquids, and application is also possible inthe case of solid contents.

Embodiment 1

In the pressurized packaging body manufacturing apparatus shown in FIGS.5-7, a spray nozzle was adopted having a nozzle orifice cross-sectionalarea of 0.44 mm² and a nozzle inclination angle of 30°. The tankinternal pressure was established at 10.0 kPa (the spray pressure atthat time was therefore 11.2 kPa). Liquefied gas inside the tank wasused as the inner purge gas, and nitrogen gas at room temperature fromnitrogen gas cylinders was used as the outer purge gas, these beinginducted, respectively. Liquid nitrogen spraying was conducted.

The nozzle temperature, spray flow volume, spray pattern spread angleand horizontal cross-sectional shape, and liquid nitrogen fine particlediameters at this time were respectively measured by the methodsdescribed below.

The nozzle temperature was measured by a thermocouple contact with theexterior of the nozzle tip in the vicinity of the nozzle orifice. Thetemperatures during spraying at that time were within a range of −180°C. to −190° C. The spray flow volume was measured by collecting sprayedliquid nitrogen into a container which is filled with liquid nitrogenand placing on the pan of an electronic balance scale, and measuring theamount of weight increase per unit time. The results indicated a sprayflow volume of 0.44 g/s under the conditions noted above. To observe thespread angle and horizontal cross-sectional shape of the spray pattern,the spray flow was received by a filter paper placed in the horizontalplane so as to cross in front of that flow, at a position of 50 mmdistant from the nozzle, and the distribution aspects of the liquidnitrogen fine particles was then investigated. As a result, thecross-sectional shape of the spray pattern was found to show a roughlyrectangular shape of narrow width, shorter in the direction of containerconveyance, as shown in FIG. 11. The maximum spray width a and maximumspray thickness b thereof were measured and found to be 43 mm and 11 mm,respectively. When the spread width thereof was measured and convertedto an angle, the spread angle β was found to be 46.5°. The sprayappearance was also shot with a high speed video camera. When the spraydiameter was measured on the resulting video, the particle diameterswere found to be distributed within a range of 0.3 to 2 mm, with a meanparticle diameter of 0.9 mm.

Such a spray condition was continued for 120 minutes. During that time,the measured values noted above were maintained, a stable spray aspectwas continued, and no frosting to the nozzle outlet was observed.Accordingly, it was demonstrated that, with the method and apparatus ofthe present invention, liquid nitrogen fine particles having a particlesize within a range of 0.3 to 2 mm are stably obtained in a prescribedspray volume (0.94 g/s in the case described above). Thus, if accuratelyinjecting liquid nitrogen fine particles sprayed from this sprayapparatus into a can, it becomes possible to inject small volume liquidnitrogen stably, that is very difficult with the conventional flow-downinjection method, and to manufacture low pressurized cans for cannedgoods which exhibit high internal pressure precision.

Embodiment 2

In order to verify this, cans were manufactured as follows with theobject of obtaining low positive pressure cans having an internal canpressure of 55 kPa (that internal pressure being higher than inEmbodiment 3 described subsequently), under the conditions noted above.

Two-piece steel can bodies having a brimful capacity of 263 ml werefilled with 240 ml of 65° C. warm water. These cans, filled with theliquid contents, were passed below the gas displacement pressurizedpackaging body manufacturing apparatus shown in FIG. 5, with thedistance between the transporting conveyor and the pressurized packagingbody manufacturing apparatus established so that the distance betweenthe nozzle tip and the filling contents surface (i.e. the spraydistance) was roughly 50 mm, and the transporting conveyor made to movewith a line speed of 76 m/min. The container headspaces were injectedwith fine particles of liquid nitrogen under stabilized sprayconditions, and seaming and sealing with aluminum lids were performedimmediately thereupon, to yield low pressurized cans.

When the injecting aspect of the liquid nitrogen spray flow into the canat that time was investigated, the spray flow was observed to have thespray width and spray thickness shown in FIG. 7, spraying angle ofinclination was observed to be 30° relative to the cans moving below,with almost all of the liquid nitrogen spray flow being injected intothe cans. When the can internal pressure of the pressurized cans thusmanufactured was measured over 120 cans, the can internal pressure wasfound to be distributed in a range of 42 kPa to 65 kPa, with a meanvalue of 53 kPa. Accordingly, internal pressures approximating thetargeted value were generated, and all of the cans were within theprescribed low pressure range.

Embodiment 3

With the object of obtaining low pressurized cans having a can internalpressure of 35 kPa, lower than in Embodiment 2 described above, 959 lowpressurized cans were manufactured under the same conditions as inEmbodiment 2 excepting in that the line speed was made high speed at 114m/min.

When the internal pressures of all of the cans thus obtained wereinspected, the can internal pressures were found to be distributedwithin a range of 29 kPa to 43 kPa. And it was demonstrated that lowpressurized cans can be stably manufactured with little fluctuation incan internal pressure even on a high speed line. This is made possiblebecause, in this apparatus, the spray flow has a velocity component inthe direction of can conveyance, so that the liquid nitrogen fineparticles can impact softly on the liquid surface, and the cans areinjected with liquid nitrogen with extremely high precision, even whenthe line speed is fast.

COMPARATIVE EXAMPLE 1

In the apparatus described above, the spray pressure was set at 201.2kPa (with a tank internal pressure of 200 kPa), and liquid nitrogen wassprayed at a spray flow volume of 2.0 g/s. Then containers were injectedwith liquid nitrogen under conditions otherwise the same as noted above.As a result, it was observed that pulsation was generated duringspraying, with an unstable spray flow spread angle, such that astabilized spray flow could not be realized. The can internal pressuresin the cans obtained were distributed over a range of 22 kPa to 75 kPa,such that low pressurized cans could not be stably obtained.

COMPARATIVE EXAMPLE 2

Here the structure was basically the same as that of the pressurizedpackaging body manufacturing apparatus shown in FIG. 5. However, thestructure here, fabricated for test purposes, was made one wherein thespray nozzle was attached horizontally at the lower end of the pipe 13.In conjunction therewith, the axis of the spray beak was made tocoincide with the spray nozzle axis, perpendicular to the direction ofcan conveyance. Then low pressurized cans were manufactured under thesame spray conditions as in Embodiment 2 but at line speeds of {circlearound (1)} 76 m/min and {circle around (2)} 114 m/min, respectively.

The results were that, in the low speed case {circle around (1)}, thecan internal pressures were distributed over a range of 32 kPa to 58kPa, so that low pressurized cans exhibiting comparatively littlefluctuation in can internal pressure could be obtained. In the case{circle around (2)} of the high speed line, however, the sprayed liquidnitrogen fine particles splashed up from the surface of the liquidcontents, and the can internal pressures were distributed over a rangeof 7 kPa to 39 kPa, such that there was great fluctuation relative tothe targeted internal pressure.

INDUSTRIAL APPLICABILITY

With the pressurized packaging body manufacturing method and apparatusof the present invention, the headspace of a packaging body such as acan for canned goods can be precisely injected with a prescribed volumeof a liquefied inert gas, such as liquid nitrogen, and the gas in thathead space can be displaced by the inert gas with a high displacementratio. The method and apparatus can therefore be employed inmanufacturing gas displacement pressurized packaging bodies such thatthe pressurized canned food, food products filled with molded cups andthe like, and are especially useful in the manufacturing of lowpressurized cans that is conventionally difficult. By applying thepresent invention, it is possible to make the can material thinner andlighter for cans of the low acid beverages and the like that readilyspoil or deteriorate, and thus to lower can costs and conserveresources.

What is claimed is:
 1. A method for manufacturing a pressurizedpackaging body comprising: providing a container filled with contentshaving a headspace; atomizing a liquefied inert gas that vaporizes toform an inert gas with liquefied fine particles, said inert gas having atemperature below final equilibrium temperature of a gas displacementpressurized body; blowing the liquefied fine particles of said liquefiedinert gas simultaneously with a low temperature inert gas into saidheadspace wherein a gas inside said headspace is displaced by said inertgas and, after sealing, an internal pressure is generated by vaporizingexpansion of remaining liquefied inert gas fine particles and thermalexpansion of said low temperature inert gas.
 2. The method formanufacturing a pressurized packaging body according to claim 1, whereinfine particles of said liquefied inert gas are generated by supplying aliquefied inert gas, while preventing vaporization thereof, by athermally insulated passageway, from a liquefied inert gas storage tankto a nozzle orifice inlet in a spray nozzle having a fine nozzleorifice, and by causing said liquefied inert gas to reveal a rapidvaporizing expansion effect immediately after discharging from saidnozzle orifice, in which other liquefied inert gas still in liquid phasestate is atomized.
 3. The method for manufacturing a pressurizedpackaging body according to either claim 1 or claim 2, wherein said lowtemperature inert gas is vaporized gas generated by boiling andvaporizing a portion of liquefied inert gas supplied under prescribedpressure to the spray nozzle.
 4. The method for manufacturing apressurized packaging body according to either claim 1 or claim 2,wherein said low temperature inert gas is vaporized gas generated byboiling and vaporization a portion of said liquefied inert gas suppliedunder prescribed pressure to the spray nozzle, and inert gas supplied byanother passageway from an inert gas supply source.
 5. The method formanufacturing a pressurized packaging body according to claim 2, whereinliquefied inert gas is sprayed from spray nozzle so that a spray patternis formed with a spread angle of 20° to 100°.
 6. The method formanufacturing a pressurized packaging body according to either claim 2or claim 5, wherein liquefied inert gas spray pattern has a horizontalcross-sectional shape that approximates a shape ranging from a square toan ellipse.
 7. The method for manufacturing a pressurized packaging bodyaccording to either claim 2 or claim 5, wherein spray flow volume ofsaid liquefied inert gas ranges from 0.2 g/s to 4.0 g/s.
 8. The methodfor manufacturing a pressurized packaging body according to either claim1 or claim 2, wherein fine particles of said liquefied inert gas have aparticle diameter that is 2 mm or less.
 9. The method for manufacturinga pressurized packaging body according to either claim 2 or claim 5,wherein spray nozzle temperature when spraying liquefied inert gasranges from boiling point of liquefied inert gas to boiling point +75°C. or less.
 10. The method for manufacturing a pressurized packagingbody according to either claim 2 or claim 5, wherein spray pressure whenspraying liquefied inert gas ranges from 1 kPa to 150 kPa.
 11. Themethod for manufacturing a pressurized packaging body according toeither claim 2 or claim 5, wherein, when spraying liquefied inert gas,said spray nozzle is isolated from outside air by vaporized gas ofcomparatively low temperature supplied from gas phase portion ofliquefied gas storage tank.
 12. The method for manufacturing apressurized packaging body according to either claim 2 or claim 5,wherein, when spraying liquefied inert gas, said spray nozzle isisolated from outside air by two layers of purge gas consisting of aninner purge gas at comparatively low temperature and an outer purge gasat comparatively high temperature.
 13. The method for manufacturing apressurized packaging body according to either claim 2 or claim 5,wherein said liquefied inert gas is sprayed at an inclination fromvertical, relative to advance of containers, of 5° to 45° so thatliquefied inert gas spray flow has a velocity component in the directionof container conveyance.
 14. The method for manufacturing a pressurizedpackaging body according to either claim 2 or claim 5, wherein the spraydistance from a tip of said spray nozzle to reaching the containerfilling surface ranges from 5 to 100 mm.
 15. The method formanufacturing a pressurized packaging body according to claim 1, 2, or5, wherein low pressurized packaging bodies having an container internalpressure, after sealing, that ranges from 0.2 to 0.8 kgf/cm², areobtained.
 16. The method for manufacturing a pressurized packaging bodyaccording to claim 1, 2, or 5, wherein said container is a metal can,and said can is spray-injected with liquefied inert gas while beingconveyed from a filler to a seamer.
 17. The method for manufacturing apressurized packaging body according to claim 1, 2, or 5, wherein saidcontainer is a metal can, said spray nozzle is deployed as an undercovergassing apparatus of a seamer, and said container is spray-injected withliquefied inert gas by undercover gassing.
 18. An apparatus formanufacturing a pressurized packaging body characterized by comprising:a liquefied inert gas storage tank and spray device having a spraynozzle deployed so as to be connected with the bottom part of saidliquefied inert gas storage tank wherein: said spray device having; avalve for controlling flow volume of a liquefied inert gas; a nozzlehaving a nozzle orifice or orifices; and a thermally insulatedpassageway for supplying the liquefied inert gas from said valve to saidnozzle orifice or orifices, means for atomizing the liquefied inert gasto form an inert gas with liquefied fine particles and to blow the fineparticles simultaneously with a low temperature inert gas having atemperature below a final equilibrium temperature of a gas displacementpressurized body.
 19. The apparatus for manufacturing a pressurizedpackaging body according to claim 18, wherein said thermally insulatedpassageway has: a liquefied inert gas flow passageway (4) from saidvalve (2) to said spray nozzle (3); and a nozzle cooling vessel (5) thatencloses outer periphery of said liquefied inert gas flow passageway (4)and cools said spray nozzle by liquefied inert gas flowing in from theliquefied inert gas storage tank (1).
 20. The apparatus formanufacturing a pressurized packaging body according to either claim 18or claim 19, wherein said spray nozzle (3, 50, 92) has a spray nozzleorifice or orifices (20, 40, 47, 51) wherein opening for sprayingliquefied inert gas as fine particles has an area ranging from 0.15 to 4mm².
 21. The apparatus for manufacturing a pressurized packaging bodyaccording to either claim 18 or claim 19, wherein said spray nozzle (3,50, 92) is deployed at an angle of inclination ranging from 5° to 45°facing downward to said vertical direction.
 22. The apparatus formanufacturing a pressurized packaging body according to either claim 18or claim 19, wherein said spray nozzle (3, 50, 92) has a plurality ofnozzle orifices.
 23. The apparatus for manufacturing a pressurizedpackaging body according to either claim 18 or claim 19, wherein saidspray device comprises purge devices for isolating at least a vicinityof an outlet of the spray nozzle from outside air and preventingfrosting.
 24. The apparatus for manufacturing a pressurized packagingbody according to claim 23, wherein said purge device comprises doublepurge gas hoods, namely an inner purge gas hood (23) forming an innerpurge gas passage (21) and an outer purge gas hood (26) forming an outerpurge gas passage (22).
 25. The apparatus for manufacturing apressurized packaging body according to either claim 18 or claim 19,wherein said spray device is attached integrally to a spray body (6) toconfigure a spray device assembly (10).
 26. The apparatus formanufacturing a pressurized packaging body according to either claim 18or claim 19, wherein said spray device is deployed in plurality at thebottom of liquefied inert gas storage tank (1, 35, 53, 70, 95).
 27. Theapparatus for manufacturing a pressurized packaging body according toeither claim 18 or claim 19, wherein said spray device is deployed incombination with liquefied inert gas flow-down device at the bottom ofliquefied inert gas storage tank.
 28. The apparatus for manufacturing apressurized packaging body according to either claim 18 or claim 19,wherein an initial purge mechanism is connected to said liquefied inertgas storage tank (1, 35, 53, 70, 95), said initial purge mechanismsupplying dry heated gas to inside of said liquefied inert gas storagetank, prior to supply of liquefied inert gas, to remove moisture frominside said tank.
 29. The apparatus for manufacturing a pressurizedpackaging body according to claim 19, wherein said spray device has: aninert gas nozzle (93) connected to an inert gas supply mechanism; and aspray nozzle (92) connected to a liquefied inert gas supply mechanism.30. The method for manufacturing a pressurized packaging body accordingto either claim 2 or claim 5, wherein spray flow volume of saidliquefied inert gas ranges from 0.2 g/s to 3.0 g/s.
 31. The method formanufacturing a pressurized packaging body according to either claim 2or claim 5, wherein spray nozzle temperature when spraying liquefiedinert gas ranges from boiling point to boiling point +50° C. or less.32. The method for manufacturing a pressurized packaging body accordingto either claim 2 or claim 5, wherein spray pressure when sprayingliquefied inert gas ranges from 1 kPa to 30 kPa.
 33. The method formanufacturing a pressurized packaging body according to either claim 2or claim 5, wherein said liquefied inert gas is sprayed at aninclination from vertical, relative to advance of containers, of 15° to40°, so that liquefied inert gas spray flow has a velocity component inthe direction of container conveyance.
 34. The method for manufacturinga pressurized packaging body according to either claim 2 or claim 5,wherein the spray distance from a tip of said spray nozzle to reachingthe container filling surface ranges from 45 to 60 mm.
 35. The apparatusfor manufacturing a pressurized packaging body according to either claim18 or claim 19, wherein said spray nozzle (3, 50, 92) has a spray nozzleorifice or orifices (20, 40, 47, 51) wherein opening for sprayingliquefied inert gas as fine particles has an area ranging from 0.2 to 3mm².
 36. The apparatus for manufacturing a pressurized packaging bodyaccording to either claim 18 or claim 19, wherein said spray nozzle (3,50, 92) is deployed at an angle of inclination ranging from 15° to 40°,facing downward to said vertical direction.